Give Above is Heat Rate for Thermal Generating Stations as defined by ASME, Performance Test Code-6, and CERC(Central Electricity Regulatory Commission, Delhi)
The Unit of Heat rate can be Kcal/Unit, or KJ/ Unit, or Btu/Unit, the Unit here in the denominator refers to Kw-hr of electricity produced at Generator Terminal.
Thus an Electric Generator Producing 300 MW-hr (MegaWattHour), consuming 720 Million Kilocalories of Heat input will have ,
Heat Rate = 2400 Kcal/Unit
The Heat Rate is generally categorized as:-
Gross Station Heat Rate and Net Station Heat rate.
If the Power generated considered in the denominator does not include the In-house or Auxilliary Power Consumed by the station then it is Known as Net Station Heat Rate other wise it is known as Gross Station Heat Rate or Station Heat Rate, In above example if we consider that the Unit/ Station has :-
Gross Power Generated = 300 MW or 300 MWHr Considering an Hour of Power Generation
Auxilliary or In house Power consumption = 21 MW or 21 MWHr considering an Hour of Power Consumption
Net Power Available Ex-Bus for Export= 279 or 279 MWHr of Net Power exported
Then Gross Station Heat Rate(GSHR)= 720 MlnKcal/300000 Units= 2400 kcal/Unit
Net Station Heat Rate(NSHR)= 720MlnKcal/(300000- 21000) Units= 2581 kcal/Unit
As per CEA(Central Electricity Authority India) Technical Standards 2010
Which Means that in case Boiler efficiency of a Supercritical unit is = 87.5%, GTCHR= 1850
and Piping lossess are 1%, then the Gross Station Heat Rate will be = 1850/(0.875x0.99)= 2135.64 Kcal/Unit
and Piping lossess are 1%, then the Gross Station Heat Rate will be = 1850/(0.875x0.99)= 2135.64 Kcal/Unit
